Along with development of an electronic welding technology, there are more and more printed circuit boards with various connector interfaces, for example, a direct plug-in Universal Serial Bus (USB) data card. There are multiple connector forms, a common USB connector is shown in FIG. 1, and the connector is defined according to a USB standard interface structure. A USB connector is placed on a printed circuit board in a manner shown in FIG. 2, wherein L is a regulation length of the USB connector extending to a part below the printed circuit board.
In the related art, a connector is usually automatically mounted and welded onto a printed circuit board in a manual welding manner or by a Surface Mounted Technology (SMT). As shown in FIG. 2, a connector is partially exposed from an edge of the printed circuit board, four pins are required to be welded onto the printed circuit board by the SMT, and other two pins are directly plugged into through holes in the printed circuit board. When a wave crest welding is adopted for welding, abnormities such as sagging or upwarping of the USB connector may easily be caused by melting of soldering tin under a condition of insufficient support or excessive support to further cause high-proportion poor welding and bring troubles to subsequent assembling and maintenance, and FIG. 3 and FIG. 4 show upwarping and sagging of the USB connector in a welding process respectively; α in FIG. 3 is an upwarping angle, and β in FIG. 4 is a sagging angle.
At present, a method for solving the above-mentioned problem is usually to temporally place a gasket below a connector on a welding tray to prevent displacement of the USB connector during reflow welding and wave crest welding. But such a method usually has the following problems of:
a poor effect, wherein conditions of sagging, upwarping or the like may still appear in the welding process;
a high cost, wherein such a tray is usually poor in universality, and different trays are required to support mounting processes of each product; according to a requirement of a current special tray on a material, a composite material with high temperature resistance and certain strength is usually adopted, such a tray usually costs 3,000 Yuan, a mounting line usually needs at least 10 trays, then tray cost is at least 30,000 Yuan, and if there are multiple mounting lines running, cost may be multiplied;
a undiversified function and a poor operability, wherein such a tray is difficult to control, and the special tray may not be applied to other projects, so that unnecessary expenditures in tray maintenance and storage are produced; and such a tray may not be accurately regulated according to practical heights of the printed circuit board and a welded device, so that a main board is likely to be skewed towards two sides after the wave crest welding.